The year is 2008.
Blackberries are still relevant forms of communication, Beyoncé is urging men everywhere to “put a ring on it”, and America’s obesity rate is clocking in at 25.5%. Recognizing the danger, a team of Harvard scientists devises a study that explores how much our genetics influence our BMI. They round up over 17,000 participants and scrutinize their genetic makeup, looking for a correlation.
The results are promising: while our genes do have a part to play, they are not the be-all and end-all of developing obesity.
The Problem
Obesity is a chronic progressive disease that is characterized by a body mass index (BMI) of 30 or more. Your BMI measures how much body fat you have based on your height and weight; it is not a perfect indicator of health, but it’s still a somewhat useful reference tool. More than 40% of the people in the United States have a BMI of over 30, and almost 10% suffer from severe obesity. The day-to-day symptoms include elevated blood pressure, languid movement, loss of sleep, and shortness of breath; however, if left unchecked, these symptoms can lead to far worse conditions.
The University of California, Davis reports that physical wellness “promotes proper care of our bodies for optimal functioning” — and while some may vehemently (and bafflingly) disagree, obesity and its symptoms do not coincide with this definition of health. Cosmetic preferences aside, it’s not medically possible to believe obesity is conducive to “optimal functioning”. We have to turn our attention to preventing further cases and to do that we must understand its roots.
The Cause
There is no singular “thing” that causes obesity. There is, however, a list of contributors that can sway someone in a healthy or unhealthy direction. Optimal health encourages a balance of “physical activity, nutrition, and mental well-being” (according to UCDavis), so a good diet and regular exercise play a large role in regulating fat retention. The mental connection we make between food and our emotional state is also a heavy contributor. (Isn’t it funny how we eat cake to console us after a bad day and to reward us after a good one?)
It’s important to note that some medical conditions like hypothyroidism and Cushing’s syndrome also promote weight gain in the body; the use of certain medications can add extra pounds on the scale as well. But medical complications aside, your lifestyle choices are the largest determinants of your health and choosing to avoid excess calories and get regular exercise can help you shed unwanted inches.
But that about the part of our lives that we can’t control, the part we’re born with and can’t get rid of? What about our genetics?
What We Know: Genetics and BMI
Despite all of our medical advancements, we still don’t understand the full relationship between genetics and obesity. There are studies that suggest adopted children are more likely to have a BMI that’s similar to their biological parents than to their adoptive ones, and there are rare single-gene defects that can cause children under the age of 2 to become obese no matter what they’re fed. Cases like these have led the scientific community to believe there is definitely a correlation between weight gain and genetics, but we have yet to discover the extent to which the two are connected.
Something we do know, though, is that a certain gene variation has been a common thread in many obesity studies. To avoid boring or confusing you, we’ll skip over the intense sciencey terms and cut right to the chase: scientists have found a strong link between (a) people who have the FTO “fat-promoting” gene variation and (b) their potential for obesity. There is a gene region called FTO that is known to facilitate weight gain when a certain gene variation exists there– and that’s where our 2008 study comes in.
The Study and What We Learned
The Harvard researchers gathered 17,508 people of Danish background and tested them for the FTO “fat-promoting” gene variation. Then they calculated each subject’s BMI and recorded their average amount of physical activity. The final step was to compare the BMIs of people who had the FTO-variance to those people who didn’t have it. The results they saw were rather interesting:
Test subjects who had the gene variance but did not get regular exercise tended to be larger than equally inactive people who didn’t have the gene. However, the presence or absence of the variance in regularly active test subjects didn’t seem to make a physical difference. In other words, having an inner “fat-promoter” wasn’t the deciding factor of the subjects’ weight– their level of activity was.
Unbeknownst to them, the subjects who exercised regularly had deactivated their bodies’ genetic tendency to cling to calories. On the flip side, long periods of inactivity provoked the gene variance to store extra fat in the participants who didn’t move around as much. The lesson we can take from this study is incredibly hopeful: genetic propensity may be able to predict whether or not someone will develop obesity, but it cannot determine it.
Conclusion: It’s (Not) All in the Genes
Looking back on those pictures of us in boho headbands and extra-wide belts, we can all agree that 2008 was a looong time ago. It’s even longer in scientific years; medical knowledge advances every hour, so we have to keep updating ourselves on its progress. In that way, a scientist’s work is never done.
Today, researchers continue to replicate and ruminate on the results of that 2008 study. A few of them, like one conducted in 2016, confirmed that having the FTO gene variance may disrupt certain weight loss methods and make it more difficult to slim down. Another from 2020 studied the biochemical variances in obese individuals and noted an additional potential influence from race-related genes. Countless studies have been based on that first experiment, and now more than ever we understand how genetic propensity can impact our lives.
So, to anyone out there who is sick of hearing “it runs in the family” or “it’s all in the genes” — don’t worry, science is sick of it, too. You can do something about it. Even if the odds are stacked against you, those odds can’t dictate your quality of life. You can take your health into your own hands. And you can start by accepting that no matter how your jeans fit right now, your genes can’t hold you back.
